Process simulation of pulp mills and biorefineries Niklas Berglin, Innventia

Transcription

1 Process simulation of pulp mills and biorefineries Niklas Berglin, Innventia 1

2 Our approach full-mill process models Allows complexity and detail without losing overview Can be developed gradually to focus on current issues Based on > 10 years experience and incorporation of sub-models from our research work 2

3 Typical questions that can be answered with full-mill process models Where do Na, S and non-process elements go? Where is energy used and wasted? How will closure options affect chemical balances, organics to effluent? Where are the risks for precipitating salts? How can we optimize purge streams? How would the installation of a new process affect mass and energy balances of the mill? How can we improve our use of secondary heat and minimize cooling needs? What flow meters can we trust?? 3

4 Theoretical mills are defined with major unit operations, mass and energy flows 4

5 But don t forget that Non-Process Elements (NPEs) are important too! Scaling problems (Al, Si, Ca, Ba, Mn) Plugging in the recovery boiler (K, Cl) Corrosion (K,Cl) Inerts in lime cycle (P, Mg, Al, Si) Peroxide bleaching (Mn, Fe, Cu) Environment (N, P, Cd, Pb, etc.) 5

6 Much detail hidden in the full-mill models Mass balances - Flow and fibre - Na, S, K and Cl - COD - NPE (Ca, Mg, Mn, Ba, etc.) - Organic compounds (Lignin, Hemi, Xylan, etc.) Energy balances - Steam - Secondary heat - Power ph COO - COO - H + O - COO - COO - Ca 2+ O - Na + Ca 2+ CaOl 2 (s) Ca 2+ R O O Ca Ca(OH) 2 (s) CaC 2 O 4 (s) temperature Ca(R-COO) + CaCO 3 (s) ionic strength 6

7 St mix Mix STORE St ore Split Mix Split Split St mix St mix Split St mix Temp 125 C PFG-TRANS_ PFG-TRANS_2 Temp 115 C 236 React 246 ion246 Split 220~1 221 Continous Digester Mix Temp 108 C WASH Wash Split Mix Mix Mix HEATX Heat x PDROP Pdrop183 Split St mix Split DILUTE Dilut e White liquor to digester 36 Mix Split Split Split 143 Split Split HEATX Heat x TALLOIL TALLOIL1 102 Split Mix91 91 STORE St ore80 80 Mix Split Split DILUTE Dilut e39 39 CNCG Mix Split 115 Mix Mix44 44 Split Split 5 5 Split Mix120 STORE St ore43 43 Split React ion React 245 ion Met eq PFG-TRANS_ PFG-TRANS_5 244 Mix Split Split 125 Split CND Cnd Mix React ion Mix Mix Split 92 Split 32 Split React ion WASH Wash86 86 Split Mix Met eq301 Split Mix Mix React 60ion60 Met eq St mix Mix41 41 Split St mix DILUTE Dilut e74 74 Met eq305~1 71 React 270 ion270 Met eq React 243 ion242 Split STORE St ore45 45 HEATX Heat x React 235 ion235 React 242 ion241 React ion46 46 React 274 ion274 Met eq Split Split 135 Split Mix React 272 ion272 Met eq306~1 305 HEATX Heat x DILUTE Dilut 61e61 Mix Split Met eq St mix49 49 Met eq BLEACHTOWER React 250 ion250 BLEACHTOWER4 65 Mix Met eq Mix Split TURB Turb DILUTE Dilut 63e63 Split React 271 ion271 Met eq BLEACHTOWER BLEACHTOWER5 TURB Turb TURB Turb HEATX Heat x STORE St ore Met eq TURB Turb BLEACHTOWER BLEACHTOWER6 76 Split PDROP Pdrop DESUP Desup React 273 ion273 Split Met eq312 STORE St ore React 241 ion St mix TURB Turb DILUTE Dilut 66e66 Met eq Mix PDROP Pdrop DESUP Desup173 Mix Mix Split Split TURB Turb Mix BLEACHTOWER BLEACHTOWER7 62 Split 153 Mix Met eq315 TURB Turb St mix Split PDROP Pdrop TURB Turb Met eq Split DESUP Desup CND Cnd Mix Mix HEATX Heat x HEATX Heat x HEATX Heat x Mix95 95 Split Met eq Mix16 54 DILUTE Dilut e85 85 LP 141 MP 140 Met eq Met eq Split Mill configuration described in WinGEMS White Liquor Flash steam Excess steam Toppcirkulation Temp 125 C AQ-make up Justering av kokningstemperaturen. Överföringscirkulation White Liquor Temp 121 C Temp 155 C MT-direct steam Energy kj/hr Ökning av temperaturen i Hi-heat tvätten Excess steam Flash Steam Till Basning Bypass digester wash Energy MJ/hr Talloil Terpentine condensor H2SO4 Restsyra From ClO2 Production Condensate Evaporators Soap Condensate Precipitants Sulf 0.35 EA EA To mix 106 Air CNCG Terpentin Na2SO4 make up Recovery boiler Ångdata HP-ånga P=81 bar MP2-ånga P=10 bar HP-ånga T=490 CMP2-ånga T=200 C MP-ånga P=26 bar LP-ånga P=4.5 bar MP-ånga T=275 CLP-ånga T=150 C Smelt dissolver tank From mud wash Green liquor clarifier Green liquor dregs White liquor filter TTA 148 g/l Energy kj/hr Energy kj/hr kg kalk tot/adt Fuel Air Slaker CaO make up uppdelat i pfg och CaO Lime kiln Lime 0.9 Flue gas Lost lime dust Lime mud Mud washer To SDT Na som Na2O i % Storeblock för uträkning av utbyte Bypass digester wash Energy MJ/hr Blåstank White liquor to chip Diffuse gaseous emissions Steam Cons: 0.1 ph:12 Chemical water O2-Stage 1 Oxygen + MgSO4 Steam O2-Stage 2 WL Losses NaOH to and rest NCG scrubber EA NaOH make up Pressure diffuser Cons: 0.1 ph:4 Chemical water Surplus Condensate: To DQ-press Chemical water Condensate to OP-press Flow 4 mt liquor/hr Flow mt liquor/hr D OP D2 Q PO Här sätter Åsa ph=8! Cons: 0.1 ph:7 Fresh water (If needed) Cons: 0.1 ph:7.5 Chemical water Chemical water To (DQ)-press Condensate Fresh water Cons: 0.1 ph:8.5 Chemical water H2SO4 Cons: 0 ph:10 To pulp dryer Flow 3 mt liquor/hr Diffuser and two wash presses Leakages (sealing water etc) Leakages wash. and dig dept. Knots and screen rejects Energy MJ/hr Spill+Spolvatten Sump with conductivity measurement Flow 10 mt liquor/hr T: 0 C Reject final screening To sewer Flow 5.3 mt liquor/hr Möjlighet till uttag för att erhålla rätt spädfaktor. To sewer Flow 5.44 mt liquor/hr Energy?b41:10 {d=2}?units To sewer Flow 2.22 mt liquor/hr Tillfört tvättvatten till blekeriet totalt :12.8 m3/adt Varav: Tillfört "Freshwater" :3.5 m3/adt Tillfört "Condensate" 4.4 m3/adt Tillfört "Fresh water to pulp dryer" 4.9 m3/adt Blekeriet Blekerie avlopp: 11.7 ton/adt Temp: 70.2 Återfört PO filtrat: 4.3 ton/adt Återfört OP filtrat: 4.3 ton/adt Bleach discharge Spill 1 kg COD Fresh water use in mill OBS! Endast rent vatten in till fabriken finns med i denna beräkning. (Kemikalie tillsater mm är inte med räknade.) To (DQ)-press To 2:nd press after PO To pulp dryer Spill+Spolvatten Total fresh water Soot blowing Flow mt/hr MT Steam Flow mt/hr LT Steam Flow mt/hr Direct steam to chip bin Flow mt/hr Steam to evaporation plant Flow mt/hr To Chemical preparation Flow mt/hr Tillfört Kemikalievatten till blekeriet totalt :1.9 m3/adt Tillfört Ång till blekeriet totalt :0.4 m3/adt Leakages wash. and dig dept. Miscellaneous losses Flow mt/hr Direct steam to Paper machine Flow mt/hr Air preheater RB mt/hr ClO mt liquor/hr Spädvatten pannor mt liquor/hr Steam 1.5 bar(a) Flow 0.12 mt/hr Steam to feed water tank mt/hr Direct steam to digester Flow mt/hr Steam to digester for heat exchange Flow mt/hr Liq steam Cond mt liquor/hr Steam to evaporation plant Flow mt/hr To O2-stages Flow mt/hr To OP-stages Flow mt/hr TURBINE COND MJ/hr GEN COOL MJ/hr CHEM PREP LIQUOR STEAM CONDENSATE EVAPORATION MJ/hr VAPOUR COND MJ/hr COOL BLEACH PLANT EFF MJ/hr COOL BLEACH PLANT EFF TERPENTINE COND MJ/hr COOL OF LIQ TO EVAP MJ/hr COOL OF LIQ TO DIG MJ/hr MJ/hr AUXILLARY WOOD YARD PULP DRYING MACHINE 2.7 mt till slut BLEACH PLANT\n CAUSTICIZING 2.22 Alkaline 0 Acidic Air preheater RB mt/hr To PO-stages Flow mt/hr To Chemical preparation Flow mt/hr Miscellaneous losses Flow mt/hr MJ/hr COOL BLP FILTRATE MJ/hr kj/hr MAKE UP WATER HEATING PULP WASHING 4.74 Miscellaneous cond mt liquor/hr Air preheater RB MT cond mt liquor/hr Digestercond mt liquor/hr Air preheater RB LT cond mt liquor/hr Pulp machine cond mt liquor/hr Chemical prep cond mt liquor/hr Miscellaneous cond mt liquor/hr 7

8 Biorefinery options modeled in UniSim COMBINED CYCLE AIR SEPARATION GASIFICATION/ GAS AND GREEN LIQUOR COOLING GAS CLEAN-UP AND CONDITIONING MeOH/DME FISCHER- TROPSCH MILL STEAM SYSTEM 8

9 Applications for the full-mill models Optimization of the process Chip Simulation model Benchmarking Condensate Flue gas ESP-dust Green liquor dregs Grits Fuel Condensate Trouble shooting O 2 Q PO D P1 Pulp dryer Dried pulp Evaluations of new equipment or new process strategies Evaluation of implementation of new sub-processes 9

10 kwh/adt Example: Benchmarking Electricity consumption Reference mill Type mill Mill A Woodyard Digester Bleachplant Evaporation Water distribution

11 Example: Benchmarking Key parameters Reference mill Type mill Mill A Water consumption COD load Electricity production Electricity consumption

12 Example: New process 12

13 Cumulative mass fraction Example: Integration of new process Methanol and DME are simple molecules that can be synthesized with high selectivity CH 3 OH CH 3 -O-CH methane 0.9 ethane Fischer-Tropsch gives mixture of products C1 C2 C3-C4 C5-C12 C13-C17 C18+ LPG naphtha diesel wax alfa

14 Boiling Point ( C) Example: Integration of new process Calculated Distillation Curve for Hydrocracker Product ASTM D86 C Diesel Naphtha 180 C 285 C 295 C 320 C 360 C Mass Percent 14

15 Bio-DME plant starting up fall of

16 Thank you! 16